Place: Naissus (Present-Day Niš, Serbia)
Details: In the years 267–269, Goths and other barbarians invaded the empire in great numbers. Sources are extremely confused on the dating of these invasions, the participants, and their targets. Modern historians are not even able to discern with certainty whether there were two or more of these invasions or a single prolonged one. It seems that, at first, a major naval expedition was led by the Heruli starting from north of the Black Sea and leading to the ravaging of many cities of Greece (among them, Athens and Sparta). Then another, even more numerous army of invaders started a second naval invasion of the empire. The Romans defeated the barbarians on sea first. Gallienus' army then won a battle in Thrace, and the emperor pursued the invaders. According to some historians, he was the leader of the army who won the great Battle of Naissus, while the majority believes that the victory must be attributed to his successor, Claudius II.